Treatment of hydrocarbon oil



Patented May 17, 1932 UNITED STATES,

FATE" JOSEPH AL SHAW, or rr'r'rsnunern, PENNSYLVANIA TREATMENT or nx'nnocannonorn 0 Drawing.

This invention relates to thetreatment ofhydrocarbon oil to remove impurities such as unsaturated organic compounds, acld-substances, and the like.

The removal of such impurities from hypolymerization of such impurities or some analogous reaction is effected, and removing the polymerized materials and the like, and then Washing the oil with analkaline liquid to remove acid substances remaining in the oil after the initial treatment of acid.- Such substances may comprise small amounts of the sulphuric acid itself,-sulphonic acids, and

sodium bicarbonate to spring the tar acid the like.

The alkaline agent generally employed in the past has been a solution of sodium hydroxide. However, it has been proposed to employfor this purpose a solution containing an alkali and an alkali salt of a tar acid; for example, a solution containing approximately equal parts of sodium hydroxide andsodium phenolate. a

There are a number of advantages; in such 7 the solutlon is not disadvantageous, W1th respect to the use of the solution in a gas puriprocedure, not the least of which is the fact that this'treatment appears to result in an improved quality of the oil after treatment with regard to color, purity, and the like. Moreover, it has been found that a process for removing phenol from still waste or other ammoniacal liquor produced by a gas plant can be advantageously operated to produce such a solution as an end product, and even in substantially the proper amount that is required for the treatment of the light oil normally removed from the coal gas produced in the same plant. I

After such a solution hasbeen employed for the treatment of the hydrocarbon oil in the manner of the prior art,it naturally contains a considerable amount of alkali sulphates, sulphonates and other analogous,

Application filed NoveniberG, 1928. Serial na'air'eea Thepresence of the former is undesirable where the solution'after treatment of the oil 'is to be used for any purpose in which its essentially alkaline nature is to beutilize'd, for example, it'has been proposed toemploy this solution to supply the necessary alkali for a known process of gas purification that comprises the treatment of'the gas with an alkaline solution for removal of acidic impurities from the gas. v w

After the liberation of the tar acid, by carbon dioxide or in an analogous manner, the

solution contains principally sodium carbonate, which 'is the active alkaline element desired. In gas purification processes of the character indicated, the sodium phenolate solution m y eadded directly to the gas purificationliquid, which contains sufiicient and produce sodium carbonate.

Such additional substances as sulphates and sulphonates that may be present in the added solution are inert with respect to the reactions involved in such a process, and their presence is decidedly undesirable as is the accumulation of any inert material in such a system. 1

On the other hand,'the tar acid content of fication 1 process of the character indicated,

and it has even been found that the presence ess or for Water softening, or the'like. In

such instance, also, the presence of inert imaterials in the solution after tar acid removal in considerable amount is undesirable.

If on the other'hand the alkaline solution after treatment ofthe oil is merely to be dis.

carded, the presence of tar acids renders this impractical or impossible by reason of the fact that modern legislation has imposed gen oral restrictions upon discharging any efi'luent'matter containing tar acids into bodies of water subsequently used for drinking purposes.

As will be apparent, the procedure above recited has advantages that make it well worth while, but it is subject'to certain disadvantages which impair its utility to a certain extent, unless suitable provisions are made. V 7

An object of the present invention is to overcome such disadvantages by providing 7 an improved processof the characterde- ,whichresults in .aesolution containing -'i the bulk of the inert productsof neutralization, but substantially free; from tar aclds.

further object of my invention is, to-provide a; process oftreating; hydrocarbon zoil with suc' h a solution in whichthere is-also produced a solution containing; the 3 bulk of thetar ,acid ordinarily present in a: vsolution employed for washing the; oil but-containing g-onlyvery limited amounts of: inert-products ,My invention has tor; further objects, such vother operative advantages or resultstaswmay herei after b eu dat obtainiMy in ntioncontemplates the usual. trea ,n entoi the hydrocarbon oilto be puri' fieclqby washing. it with sulphuric acid; in-the usual manner. The oil- :is agitated with the-i-approcomprises a solution of free acid, sodium sulphate, sodium sulphonates and the like, but is substantially free from tar acid.

After this initial treatment the oil contains some unneutralized acid substances together with substantially all of the tar acid original- 7. ly, containedin the initial washing liquid.

I t-ity of the washing solution containing alkali and alkali salt of tar acid as before, in sufiicient amount to complete the neutralization of the remaining acid substances present inthe oil after the acid washing treatment andalso the tar acids contained, by the oil after the first alkaline washinglst-age.

.Afteraagitation and settling, the aqueous 'layeris ldraw-n off as before,tbut isznot allowed to mingle with the. aqueous liquid withdrawn after the first alkaline washing stage.

-.-neu;tralization, and .may. also contain small -amounts=of unconsumed sodium hydroxide.

;By reason of the fact that the :SOllllilOD withdrawn; after ,the -first stage containsrsub- :sta-ntially,-.-n0. tan acids, itcmay readily: bedis- V i cardedorwutilizedinany'manner withoutthe adifficulty qwhich wouldi otherwise :bBzDBCBSSl tated: by, the'preseneeoftar acidsor taracid ,compoundstherein. 1 V

By reason of the fact that the-solution Thiseaqueous. liquorewithd'rawnaafter the Priflte q n y r fli 11 th required time, withdraw-I1 from a the secondualkali washing andthe resultant aqueo-usAayer containing ,stageucontainsonlya verysmallamountfot the bulkjot the excess acid and-the polymerinertproductsof neutralization, it may-readr ized hydrocarbon impurities is withdrawn ,ly beemployed:without,disadvantagefor-use ingtheQformofaslu-dge.and eithersdiscarded gin gas purification, water softeninggortfor or treated inany suitable manner. 1 As; above, recited the oil-nowcontains-appreciable amounts of acid impuritiescornpr ng, principal y nlphoai acidsand us a ly? some of: the excess. su phu ic acid itself. v l or the purpose-ofremoving these acid impurities, I, employz-a solution of alkalig-andan [alkali salt ota a a i fe .e mple, ia solu- 1 t on otod um; hydroxide and sodiump olate. V I

AcQOrdingrto my invention, -:1 accomplish this treatment: of the! oil, in; twostages, using inithe first: stage an amoun -10 the washing ,.p .ete1y 1 neu ra i e acid -suhstan e :co

. tained, in. the oil. The oil is agitatedwith this amount of th o utio l h iusua anner- The free alkali ,in the solutionfirst gI-fGflClZS with the acidssllbstancesin the oiliuntil it is exhausted, and, the tar acids present are then ,Ii-beratedby aportion o'fqthe,remaining-acid substances in. the oil. sflhegliberated tan-acids slightly acid aqueous, layer is withdrawn. It

other purpose with or :without prelimi- .nary liberation.- of, tarzac-ids, as; the situation may require. {fact that itcontains substantially all: of the '2 tar acid originally, contained. in all 1 of the -.S0luti0 n;.uSed for the, firstand second, alkaline washing treatments, :it may? be treated with comparative easefor the: recovery of. theit'fll :acid iwhensso desired.

,HThQoilis then treated'with a further quan- ICC Moreover, by :reason of :the

iii)

In general I prefer to ,employifor the alka- I line washing stages :3, =,solution.containing substantially equal J parts of; sodium hydroxide andsodium phenolate or sodium salts of other tar ;acids, but t-hisratio need not be adhered to and-willgin tactva-ry' considerably .,in difi'erenuplants, as will :be yevidentirom the above description.

.Itis in general-desirable to employ-a suflicient excessof alkaliin-the phenol removal .plant'toinsure-that the I'GSllltitIlfiSOllltlOIliOf V alkali and alkali tar V-acid compound is sufii- ,.cient in amount to satisfy -the=washing requirements :for the :light oil norm-ally ire- .COVQIBdT from-the gasimadeiin the same plant,

and-therequirementsofoneqolant may differ considerably fromthoseofzanotheri IIntone plant, this procedure required that the alkaline solution leaving the phenol removal plant be only saturated with respect to tar acids.

It is desirable and in many circumstances necessary for the solution to have a sufiicient concentration of free alkali to make it possible to recapture in the second stage all of the tar acid transferred to the oil in the first stage, without the employment of excessive amounts of washing solution, unless such amounts are produced as a matter of course in the operation of the phenol removal process in the same plant.

The actual amounts of alkaline tar acid solution employed for Washing in the first and second stages are determined by the operator in accordance with the desired quality of product. Consequently, no specific figures would be of value as in each case the total quantities necessary and the quantities necessary in the first and second stages will vary according to the character of the oil, and also the nature of the acid washing stage.

It is important if substantially complete freedom from tar acid in the effluent from the first alkaline washing stage is desired that this first stage should fall a little short of com plete neutralization of the acid impurities in the oil, in order that there will be a suificient amount of acid impurities over and above the amount neutralized by the free alkali to effect the substantially complete springing of the tar acid from its alkali compound.

However, if for any reason it is more desirable that the efHuent from the second stage should contain no sodium sulphate or the like than that the effluent from the first stage should be substantially free from tar acid, then the initial stage may be carried to a point where substantially complete neutralization of the acid impurities in the oil is effected.

The term tar acid as used herein refers not only to phenol alone, but to cresol and analogous substances designated generally under this heading.

l'Vhile my invention has been described hereinabove with respect to certain illustrative examples, it is not limited to such specific examples, but is to be construed as of the scope of the claims hereinafter made.

I claim as my invention 1. The process of removing acid substances from hydrocarbon oil after treatment thereof with sulphuric acid which comprises washing said oil with a solution of a salt of a tar acid and an alkali-forming metal, and containing free alkali, in two stages, the solution used in the first stage being just insuflicient to completely neutralize the acid substances present in said hydrocarbon oil, and said solution being removed from the oil prior to the second stage, and the solution used in the second stage being suflicient to complete said neutralization and to remove substantially all tar acid derived by said oil in said first stage. j g

2. The process of removing acid substances from hydrocarbon oil aftertreatment thereof with sulphuric acid which comprises washing said oil with a solution of sodium hydroxide and sodium phenolate, in two stages, the

3. The process of removing acid substances from hydrocarbon oil after treatment thereproximately equal parts of sodium hydroxide I and sodium phenolate, in two stages, the solution used in the first stage being just insufiicient to completely neutralize the acid substances present in said hydrocarbon oil, and said solution being removed from the oil prior to the second stage, and the solution used in the second stage being sufficient tocomplete said neutralization and to remove substantially all tar acid derived by said oil in said first stage.

4. The process of removing acid substances from hydrocarbon oil after treatment thereof with sulphuric acid, which comprises washing said oil with a solution containing a compound of a tar acid and an alkali-forming metal, said solution being used in amount just insufficient to completely neutralize the acid substances present in said hydrocarbon oil after said treatment with sulphuric acid, removing said solution from contact with the oil and then washing the oil with a solution containing an alkali in amount suflicient to complete the neutralization of said acid substances and to remove substantially all tar acid derived by said oil during said first washing.

In testimony whereof, I have hereunto subscribed my name this third day of November,

JOSEPH A. SHAW.

of with sulphuric acid which comprises wash.- 5-

ing said oil with a solution containing ap 

